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    * The ASF licenses this file to You under the Apache License, Version 2.0
    * (the "License"); you may not use this file except in compliance with
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    *
    *      http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
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   * See the License for the specific language governing permissions and
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  package org.apache.commons.math4.legacy.stat.inference;
  
  import org.apache.commons.math4.legacy.exception.DimensionMismatchException;
  import org.apache.commons.math4.legacy.exception.NotPositiveException;
  import org.apache.commons.math4.legacy.exception.NotStrictlyPositiveException;
  import org.apache.commons.math4.legacy.exception.OutOfRangeException;
  import org.apache.commons.math4.legacy.exception.ZeroException;
  import org.junit.Assert;
  import org.junit.Test;
  import org.junit.jupiter.api.Assertions;
  
  
  /**
   * Test cases for the ChiSquareTestImpl class.
   *
   */
  
  public class ChiSquareTestTest {
  
      protected ChiSquareTest testStatistic = new ChiSquareTest();
  
      @Test
      public void testChiSquare() {
  
          // Target values computed using R version 1.8.1
          // Some assembly required ;-)
          //      Use sum((obs - exp)^2/exp) for the chi-square statistic and
          //      1 - pchisq(sum((obs - exp)^2/exp), length(obs) - 1) for the p-value
  
          long[] observed = {10, 9, 11};
          double[] expected = {10, 10, 10};
          Assert.assertEquals("chi-square statistic", 0.2,  testStatistic.chiSquare(expected, observed), 10E-12);
          Assert.assertEquals("chi-square p-value", 0.904837418036, testStatistic.chiSquareTest(expected, observed), 1E-10);
  
          long[] observed1 = { 500, 623, 72, 70, 31 };
          double[] expected1 = { 485, 541, 82, 61, 37 };
          Assert.assertEquals( "chi-square test statistic", 9.023307936427388, testStatistic.chiSquare(expected1, observed1), 1E-10);
          Assert.assertEquals("chi-square p-value", 0.06051952647453607, testStatistic.chiSquareTest(expected1, observed1), 1E-9);
          Assert.assertTrue("chi-square test reject", testStatistic.chiSquareTest(expected1, observed1, 0.08));
          Assert.assertFalse("chi-square test accept", testStatistic.chiSquareTest(expected1, observed1, 0.05));
  
          try {
              testStatistic.chiSquareTest(expected1, observed1, 95);
              Assert.fail("alpha out of range, OutOfRangeException expected");
          } catch (OutOfRangeException ex) {
              // expected
          }
  
          long[] tooShortObs = { 0 };
          double[] tooShortEx = { 1 };
          try {
              testStatistic.chiSquare(tooShortEx, tooShortObs);
              Assert.fail("arguments too short, DimensionMismatchException expected");
          } catch (DimensionMismatchException ex) {
              // expected
          }
  
          // unmatched arrays
          long[] unMatchedObs = { 0, 1, 2, 3 };
          double[] unMatchedEx = { 1, 1, 2 };
          try {
              testStatistic.chiSquare(unMatchedEx, unMatchedObs);
              Assert.fail("arrays have different lengths, DimensionMismatchException expected");
          } catch (DimensionMismatchException ex) {
              // expected
          }
  
          // 0 expected count
          expected[0] = 0;
          try {
              testStatistic.chiSquareTest(expected, observed, .01);
              Assert.fail("bad expected count, NotStrictlyPositiveException expected");
          } catch (NotStrictlyPositiveException ex) {
              // expected
          }
  
          // negative observed count
          expected[0] = 1;
          observed[0] = -1;
          try {
              testStatistic.chiSquareTest(expected, observed, .01);
              Assert.fail("bad expected count, NotPositiveException expected");
          } catch (NotPositiveException ex) {
             // expected
         }
     }
 
     @Test
     public void testChiSquareIndependence() {
 
         // Target values computed using R version 1.8.1
 
         long[][] counts = { {40, 22, 43}, {91, 21, 28}, {60, 10, 22}};
         Assert.assertEquals( "chi-square test statistic", 22.709027688, testStatistic.chiSquare(counts), 1E-9);
         Assert.assertEquals("chi-square p-value", 0.000144751460134, testStatistic.chiSquareTest(counts), 1E-9);
         Assert.assertTrue("chi-square test reject", testStatistic.chiSquareTest(counts, 0.0002));
         Assert.assertFalse("chi-square test accept", testStatistic.chiSquareTest(counts, 0.0001));
 
         long[][] counts2 = {{10, 15}, {30, 40}, {60, 90} };
         Assert.assertEquals( "chi-square test statistic", 0.168965517241, testStatistic.chiSquare(counts2), 1E-9);
         Assert.assertEquals("chi-square p-value",0.918987499852, testStatistic.chiSquareTest(counts2), 1E-9);
         Assert.assertFalse("chi-square test accept", testStatistic.chiSquareTest(counts2, 0.1));
 
         // ragged input array
         long[][] counts3 = { {40, 22, 43}, {91, 21, 28}, {60, 10}};
         try {
             testStatistic.chiSquare(counts3);
             Assert.fail("Expecting DimensionMismatchException");
         } catch (DimensionMismatchException ex) {
             // expected
         }
 
         // insufficient data
         long[][] counts4 = {{40, 22, 43}};
         try {
             testStatistic.chiSquare(counts4);
             Assert.fail("Expecting DimensionMismatchException");
         } catch (DimensionMismatchException ex) {
             // expected
         }
         long[][] counts5 = {{40}, {40}, {30}, {10}};
         try {
             testStatistic.chiSquare(counts5);
             Assert.fail("Expecting DimensionMismatchException");
         } catch (DimensionMismatchException ex) {
             // expected
         }
 
         // negative counts
         long[][] counts6 = {{10, -2}, {30, 40}, {60, 90} };
         try {
             testStatistic.chiSquare(counts6);
             Assert.fail("Expecting NotPositiveException");
         } catch (NotPositiveException ex) {
             // expected
         }
 
         // bad alpha
         try {
             testStatistic.chiSquareTest(counts, 0);
             Assert.fail("Expecting OutOfRangeException");
         } catch (OutOfRangeException ex) {
             // expected
         }
     }
 
     @Test
     public void testChiSquareLargeTestStatistic() {
         double[] exp = new double[] {
             3389119.5, 649136.6, 285745.4, 25357364.76, 11291189.78, 543628.0,
             232921.0, 437665.75
         };
 
         long[] obs = new long[] {
             2372383, 584222, 257170, 17750155, 7903832, 489265, 209628, 393899
         };
         org.apache.commons.math4.legacy.stat.inference.ChiSquareTest csti =
             new org.apache.commons.math4.legacy.stat.inference.ChiSquareTest();
         double cst = csti.chiSquareTest(exp, obs);
         Assert.assertEquals("chi-square p-value", 0.0, cst, 1E-3);
         Assert.assertEquals( "chi-square test statistic",
                 114875.90421929007, testStatistic.chiSquare(exp, obs), 1E-9);
     }
 
     /** Contingency table containing zeros - PR # 32531 */
     @Test
     public void testChiSquareZeroCount() {
         // Target values computed using R version 1.8.1
         long[][] counts = { {40, 0, 4}, {91, 1, 2}, {60, 2, 0}};
         Assert.assertEquals( "chi-square test statistic", 9.67444662263,
                 testStatistic.chiSquare(counts), 1E-9);
         Assert.assertEquals("chi-square p-value", 0.0462835770603,
                 testStatistic.chiSquareTest(counts), 1E-9);
     }
 
     /** Target values verified using DATAPLOT version 2006.3 */
     @Test
     public void testChiSquareDataSetsComparisonEqualCounts() {
         long[] observed1 = {10, 12, 12, 10};
         long[] observed2 = {5, 15, 14, 10};
         Assert.assertEquals("chi-square p value", 0.541096,
                 testStatistic.chiSquareTestDataSetsComparison(
                 observed1, observed2), 1E-6);
         Assert.assertEquals("chi-square test statistic", 2.153846,
                 testStatistic.chiSquareDataSetsComparison(
                 observed1, observed2), 1E-6);
         Assert.assertFalse("chi-square test result",
                 testStatistic.chiSquareTestDataSetsComparison(
                 observed1, observed2, 0.4));
     }
 
     /** Target values verified using DATAPLOT version 2006.3 */
     @Test
     public void testChiSquareDataSetsComparisonUnEqualCounts() {
         long[] observed1 = {10, 12, 12, 10, 15};
         long[] observed2 = {15, 10, 10, 15, 5};
         Assert.assertEquals("chi-square p value", 0.124115,
                 testStatistic.chiSquareTestDataSetsComparison(
                 observed1, observed2), 1E-6);
         Assert.assertEquals("chi-square test statistic", 7.232189,
                 testStatistic.chiSquareDataSetsComparison(
                 observed1, observed2), 1E-6);
         Assert.assertTrue("chi-square test result",
                 testStatistic.chiSquareTestDataSetsComparison(
                 observed1, observed2, 0.13));
         Assert.assertFalse("chi-square test result",
                 testStatistic.chiSquareTestDataSetsComparison(
                 observed1, observed2, 0.12));
     }
 
     @Test
     public void testChiSquareDataSetsComparisonBadCounts() {
         long[] observed1 = {10, -1, 12, 10, 15};
         long[] observed2 = {15, 10, 10, 15, 5};
         try {
             testStatistic.chiSquareTestDataSetsComparison(
                     observed1, observed2);
             Assert.fail("Expecting NotPositiveException - negative count");
         } catch (NotPositiveException ex) {
             // expected
         }
         long[] observed3 = {10, 0, 12, 10, 15};
         long[] observed4 = {15, 0, 10, 15, 5};
         try {
             testStatistic.chiSquareTestDataSetsComparison(
                     observed3, observed4);
             Assert.fail("Expecting ZeroException - double 0's");
         } catch (ZeroException ex) {
             // expected
         }
         long[] observed5 = {10, 10, 12, 10, 15};
         long[] observed6 = {0, 0, 0, 0, 0};
         try {
             testStatistic.chiSquareTestDataSetsComparison(
                     observed5, observed6);
             Assert.fail("Expecting ZeroException - vanishing counts");
         } catch (ZeroException ex) {
             // expected
         }
     }
 
     @Test
     public void testChiSquareWithZeroObservations() {
         // No counts
         final long[][] counts = new long[2][2];
         Assertions.assertThrows(ZeroException.class, () -> testStatistic.chiSquare(counts));
         // Empty column
         final long[][] counts2 = {{1, 2, 0}, {3, 4, 0}};
         Assertions.assertThrows(ZeroException.class, () -> testStatistic.chiSquare(counts2));
         // Empty row
         final long[][] counts3 = {{1, 2}, {3, 4}, {0, 0}};
         Assertions.assertThrows(ZeroException.class, () -> testStatistic.chiSquare(counts3));
     }
 }